Cargo is commonly transported from a loading dock to a waiting aircraft by a motorized cargo transporter. Typical cargo transporters have a flat cargo platform for receiving and transporting the cargo. The cargo is then moved from the cargo platform to the cargo deck of the aircraft. Obviously, it greatly facilitates the loading of the aircraft if the cargo platform and the cargo deck are at the same height.
The cargo decks on different types of aircraft are located at different heights above ground level. The heights of cargo decks range from eighteen and a half feet, on the Boeing 747, to thirty-nine inches on the C-130. Therefore, if a single cargo transporter is to be used with several different types of aircraft, the height of the cargo platform of the cargo transporter must be adjustable.
Cargo transporters typically have a frame with wheel assemblies at each end. A cargo platform is mounted on the frame, and lift assemblies are mounted between the frame and the cargo platform. The lift assemblies raise and lower the cargo platform relative to the frame of the transporter.
Some cargo transporter lift assemblies have a pair of scissor arms. Apparatus is provided for changing the angle between the scissor arms, in order to raise or lower the platform relative to the frame.
In many cases it is desirable to load the cargo transporter itself into an aircraft. Sometimes the ground clearance under the frame of the cargo transporter is insufficient to allow the transporter to get over the angle between the ramp and the cargo deck of the aircraft.
The present invention relates to a cargo transporter which overcomes the foregoing deficiencies long since associated with the prior art. The cargo transporter of the invention has a cargo platform mounted on a frame that is supported by two pairs of lift assemblies. Each lift assembly is in turn mounted on a wheel assembly. Importantly, neither the wheel assemblies nor the lift assemblies are interconnected by any sort of frame other than the cargo platform frame.
Each lift assembly has an elongated leg connected to the frame at one end and to a wheel assembly at the other end. A support arm is pivotally connected at one end to the frame end and is pivotally connected at the other end to the leg. Hydraulic cylinders are used to change the angles between the support arms and the legs in a scissor-like fashion. As the angles are changed, the upper ends of the legs slide horizontally along the frame, and the frame and the cargo platform are raised or lowered. The lift assemblies are located far enough apart so that the upper ends of the legs do not contact when the cargo platform is in the lowermost position.
The cargo platform is mounted on the frame by a set of hydraulic cylinders that allow the platform to be moved slightly relative to the frame. The platform can be moved laterally or longitudinally, tilted, or pivoted about a vertical axis. These movements allow the operator to make fine adjustments in the alignment between the platform and the cargo deck of the aircraft.